A wide variety of systems and methods exist for performing biochemical analysis, for example for medical testing. A common technique is to load analytes and reagents into a microfluidic “chip” that has fluid flow channels and other structures formed in it using photolithography techniques. Such a chip may include pumps, reservoirs, valves, mixing structures, and other features useful in the performance of a certain tests.
Typically, such a chip is controlled by an external controller, through application and release of fluid pressure at key points in the chip. For example, a valve may be formed by crossing a fluid flow channel in a soft medium with a dead-end cross channel. By pressurizing the cross channel, the fluid flow channel can be pinched off, and by releasing the pressure in the cross channel, the fluid flow channel is allowed to re-open. A peristaltic pump may be formed by placing three or more such valves close together crossing a fluid flow channel in a soft medium. By sequentially pressurizing and depressurizing the valves channels to pinch off and re-open adjacent locations in the fluid flow channel, fluid can be caused to flow in the fluid flow channel.
Because of the need for complex external pressure control, such microfluidic chips are not convenient for use in routine medical testing, especially in remote locations.